If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

Detection of Schmallenberg virus in bull semen

Detection of Schmallenberg virus RNA in semen samples
-----------------------------------------------------
In the framework of a study co-financed by the European Union, the Friedrich-Loeffler-Institut (FLI) analyzed the semen of bulls with a known SBV-antibody status for the presence of Schmallenberg virus (SBV) genome. All samples were investigated with an optimized RNA extraction method and a real-time RT-PCR (RT-qPCR) system developed and established at the FLI.

At present, 740 semen batches from 94 SBV-infected and seroconverting/seroconverted bulls have been analyzed.26 semen batches from 11 bulls reacted positive in the RT-qPCR analyses with Cq-values from 26 to 37. In 3 of the 11 bulls with SBV-genome positive semen samples, also 1st SBV-antibodies could be detected. In 2 bulls SBV-genome could be detected for more than 40 days in 6 or 8 consecutive semen batches, respectively. Furthermore, in one bull a pattern of PCR-positive and PCR-negative consecutive semen batches was observed within 43 days (5 batches positive / 2 batches negative / 2 batches positive / 2 batches negative / 1 batch positive). This points to intermitting virus excretion in semen. However, it is currently unclear and topic of further studies, how long after seroconversion this situation may persist.

In addition, in vitro and in vivo studies about the infectivity of the SBV-positive semen samples are ongoing.

The Central Veterinary Institute (CVI) of Wageningen University and Research Centre in Lelystad, the Netherlands, and the French Agency for Food and Environmental and Occupational Health and Safety (ANSES) can confirm from their own observations the detection of Schmallenberg virus [SBV] RNA in semen samples, as reported by the Friedrich-Loeffler-Institut on 19 Dec 2012.

At CVI, 55 semen samples produced in 2012 by 8 seroconverting/viraemic bulls have been analysed using a real-time RT-PCR system developed by FLI and an RNA extraction method developed by CVI. In total, 3 samples produced by 2 different bulls tested positive.

At LNCR (National Laboratory for sanitary controls in breeding animals, France) together with ANSES, 904 semen samples produced in 2011 and 2012 by 160 seropositive bulls have been analysed using a real-time RT-PCR system developed by FLI and an RNA extraction method developed by LNCR. In total 26 samples produced by 2 different bulls were tested positive for 2 to 3 months.

Because of these findings, the institutes are currently performing in vitro and in vivo studies on SBV excretion in semen. These studies are supported by the European Union and the national governments.

In the meantime, to declare semen free of SBV, it is advised to test semen samples for the presence of SBV RNA using an approved RT-PCR and RNA extraction method, unless the semen was produced before 31 May 2011 or the bull was tested SBV antibody negative at least 28 days after production.

Prof Dr Wim H M van der Poel (Department of Virology)

Dr Ruth Bouwstra, Dr Johan Bongers (Department of Diagnostics)

Central Veterinary Institute of Wageningen University and Research Centre, Lelystad, the Netherlands.

Dr Stephan Zientara, French Agency for Food and Environmental and Occupational Health and Safety;

Recently, the Friedrich-Loeffler-Institut (FLI) reported about the detection of Schmallenberg virus (SBV)-genome in semen. In 26 semen batches from 11 bulls, SBV-genome could be detected by real-time RT-PCR.

For verification of the infectious status of SBV-positive semen batches, 6 calves were experimentally inoculated in a 1st study. Each animal received pooled semen of 5 straws from one semen batch subcutaneously. The selected semen batches originated from 6 different bulls and represented batches with variable SBV-genome loads. Following inoculation, no clinical symptoms were seen in the animals.

However, for 2 of the 6 calves, an SBV infection could be confirmed by both real-time RT-PCR and subsequent SBV-seroconversion. In 4 of the 6 calves, neither SBV-genomes nor SBV-antibodies could be detected. The 2 semen batches which led to infection of inoculated animals had Cq-values of 26.4 and 34.2, respectively.

Based on those data, it has to be concluded that samples with a medium as well as with a low viral genome load (Cq values over 30) can be potentially infectious for bovines. These results confirm the requirement for a sensitive viral RNA-extraction as well as SBV-genome detection system for testing of semen from SBV-infected bulls.

[The above, firsthand information is gratefully acknowledged. In a previous report from same German authors, they indicated that intermittent SBV excretion was observed in semen of SBV-positive bulls in some of the cases (posting 20121220.1460864). These observations have been confirmed in Dutch and French institutes. They indicate that SBV behaves differently from another Simbu-group teratogenic virus, namely Akabane virus (in Australia).

The current report provides intermediate results of the ongoing research on the issue. The experiment calves were inoculated subcutaneously with the semen. It may be anticipated that the actual potential infectivity of SBV semen will also be tested by insemination.

These essential studies are meant to facilitate the data enabling a science-based decision upon the need for international requirements, including tests, as conditional for trade in semen from SBV-positive/suspected bulls and from SBV-infected zones or countries. - Mod.AS]

“Addressing chronic disease is an issue of human rights – that must be our call to arms"
Richard Horton, Editor-in-Chief The Lancet

After inoculation (at day 0), semen was collected daily from both animals for 21 days and samples were tested for SBV by qRT–PCR assay.

At 24 days post-inoculation both animals were subjected to necropsy and the genital organs and lymph nodes draining these organs were also tested for SBV RNA (qRT–PCR).

After SBV infection both animals in the study showed viraemia (qRT–PCR) with fever and diarrhoea. SBV RNA could be detected in semen from both animals. The highest SBV RNA concentrations in semen were found in the first week (days 4–7 post-inoculation) but concentrations were relatively low (Ct values 30–39).

Viable SBV was only isolated from blood samples and not from semen or genital tissues.

Comment

The reader is responsible for discerning the validity, factuality or implications of information posted here, be it fictional or based on real events. Moderators on this forum make every effort to review the material posted on this site however, it is not realistically possible for our staff to manually review each post.

The content of posts on this site, including but not limited to links to other web sites, are the expressed opinion of the original authors or posters and are not endorsed by, or representative of the opinions of, the owners or administration of this website. The posts on this website are the opinion of the specific author or poster and should not be construed as statements of advice or factual information.

Not all posts on this website are intended as truthful or factual assertion by their authors. NO posts on this website should be considered factual information on face value alone. Users are encouraged to USE DISCERNMENT and do their own follow up research while reading and posting on this website. FluTrackers.com Inc. reserves the right to make changes to, corrections and/or remove entirely at any time posts made on this website without notice. In addition, FluTrackers.com Inc. disclaims any and all liability for damages incurred directly or indirectly as a result of a post on this website.

This site is provided "as is" without warranty of any kind, either expressed or implied. You should not assume that this site is error-free or that it will be suitable for the particular purpose which you have in mind when using it. In no event shall FluTrackers.com Inc. be liable for any special, incidental, indirect or consequential damages of any kind, or any damages whatsoever, including, without limitation, those resulting from loss of use, data or profits, whether or not advised of the possibility of damage, and on any theory of liability, arising out of or in connection with the use or performance of this site or other documents which are referenced by or linked to this site.

Finally, FluTrackers.com Inc. reserves the right to delete, correct, or make changes to any post on this website without notice at any time for any reason.

Fair Use Notice:
This site may contain copyrighted material the use of which has not always been specifically authorized by the copyright owner. Users may make such material available in an effort to advance awareness and understanding of issues relating to public health, civil rights, economics, individual rights, international affairs, liberty, science & technology, etc. We believe this constitutes a 'fair use' of any such copyrighted material as provided for in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C.Section 107, the material on this site is distributed to those who have expressed a prior interest in receiving the included information for research and educational purposes.

In accordance with industry accepted best practices we ask that users limit their copy / paste of copyrighted material to the relevant portions of the article you wish to discuss and no more than 1 paragraph, and in no case more than 50% of the source material provide a link back to the original article and provide your original comments / criticism in your post with the article. Please remember you are responsible for what you post on the internet and you could be sued by the original copyright holder if you do not honor these rules.

If you are a legal copyright holder or a designated agent for such and you believe a post on this website falls outside the boundaries of "Fair Use" and legitimately infringes on yours or your clients copyright

In accordance with section 512 of the U.S. Copyright Act our contact information has been registered with the United States Copyright Office. "Safe Harbor" noticing procedures as outlined in the DMCA apply to this website concerning all 3rd party posts published herein.

If notice is given of an alleged copyright violation we will act expeditiously to remove or disable access to the material(s) in question.

All 3rd party material posted on this website is the copyright of the respective owners / authors. FluTrackers.com Inc. makes no claim of copyright on such material.

Please be aware any communications sent complaining about a post on this website may be posted publicly at the discretion of the administration.

FluTrackers Does Not Provide Any Medical Advice:

FluTrackers, Inc. does not provide medical advice. Information on this web site is collected from various internet resources, and the FluTrackers board of directors makes no warranty to the safety, efficacy, correctness or completeness of the information posted on this site by any author or poster.

The information collated here is for instructional and/or discussion purposes only and is NOT intended to diagnose or treat any disease, illness, or other medical condition. Every individual reader or poster should seek advice from their personal physician/healthcare practitioner before considering or using any interventions that are discussed on this website.

By continuing to access this website you agree to consult your personal physican before using any interventions posted on this website, and you agree to hold harmless FluTrackers.com Inc., the board of directors, the members, and all authors and posters for any effects from use of any medication, supplement, vitamin or other substance, device, intervention, etc. mentioned in posts on this website, or other internet venues referenced in posts on this website.

By using and/or accessing this site, either passively or actively, you are agreeing to all of the above conditions. Also, by using and/or accessing this site, either passively or actively, you agree to conduct all business and legal affairs related to this website in the jurisdiction of Flutrackers.com Inc. which is registered in Central Florida, USA.

These Disclaimers are subject to change at anytime.

Email the Webmaster with questions or comments about this site at flutrackers@earthlink.net